"one who plays the pipes," Old English pipere, agent noun from pipe (v.). By late 14c. also "a bag-piper." As a kind of fish, from c. 1600. Figurative expression pay the piper is recorded from 1680s.

1550s, from German Pfeife "fife, pipe," from Old High German pfifa; the English word is perhaps via French fifre (15c.) from the same Old High German word. Ultimately imitative (see pipe (n.1)). German musicians provided music for most European courts in those days. As a verb from 1590s. Agent noun fifer is recorded earlier (1530s). Fife and drum is from 1670s.

type of bagpipe music consisting of a series of variations on a theme, 1719, from Gaelic piobaireachd, literally "piper's art," from piobair "a piper" (from piob "pipe," an English loan word; see pipe (n.1)) + -achd, suffix denoting function.

the sort of improbable fantasy one has while smoking opium, 1870, from pipe (n.1) in the smoking sense + dream (n.). Old English pipdream meant "piping," from dream in the sense of "music."

also pipefish, fish with a long, tubular snout, by 1769, from pipe (n.1) + fish (n.).

1859, "continuous conduit of pipes chiefly laid underground," from pipe (n.1) + line (n.). Figurative sense of "channel of communication" is from 1921; surfer slang meaning "hollow part of a large wave" is attested by 1963.